JP7497590B2 - Static electricity removing device and image forming apparatus - Google Patents

Description

The present invention relates to a static eliminator and an image forming apparatus.

The following patent documents 1 and 2 disclose techniques for a static eliminator that eliminates static electricity from the surface of an image holding means in an image forming device such as a copier, printer, or facsimile.

JP 2009-271358 A, which is a patent document 1, describes a configuration in which an erase lamp (16) that discharges electricity from a photosensitive drum (11) is turned off when the entire width of the photosensitive drum (11) does not require discharge, and the erase lamp (16) is turned on when discharge is required even in a portion of the photosensitive drum (11). Patent document 1 also describes a configuration in which the multiple LEDs that make up the erase lamp (16) are divided into three regions in the width direction, and the LEDs in the three regions are individually turned on/off with switches (SW1 to SW3), and the LEDs are controlled to be turned on/off by determining whether discharge is required in each of the three regions. Patent document 1 also describes a configuration in which two lamps, an erase lamp that can discharge a wide region and an erase lamp that can discharge a narrow region, are arranged side by side, and the erase lamps are switched.

Patent Document 2, JP 2003-248400 A, describes a configuration in which a static eliminator (34) is equipped with three LED rows (34a-34c) with different widths that can eliminate static electricity, and the three LED rows (34a-34c) can be switched by transistors (35a-35c). In the technology described in Patent Document 2, the LED row (34a-34c) to be used is switched according to the width of the paper passing area, which is the width of the paper being used, and the amount of light irradiated to the photoconductor (9) is adjusted so that it is lower outside the paper passing area than inside the paper passing area.

JP 2009-271358 A ("0033"-"0036", "0046"-"0049", "0066"-"0067", Figs. 3, 8, 13) JP 2003-248400 A ("0019"-"0021", FIG. 2)

The technical objective of the present invention is to simplify the configuration compared to providing separate static elimination means for multiple regions in the width direction.

In order to solve the above technical problem, the static eliminator of the invention described in claim 1 comprises:
a light emitting means having a plurality of light emitting elements arranged along a direction of a rotation axis of the rotating image holding means, and irradiating the image holding means with light;
A control means for controlling the lighting of the light emitting element;
Equipped with
the distribution of the amount of light in the direction of the rotation axis is such that the amount of light is greater in the central portion in the width direction of the medium on which the image is recorded than in the end portions;
the light emitting means has an optical element disposed between the light emitting element and the image holding means for reducing the amount of light at the end portion compared to the amount of light at the central portion;
The optical element is formed in a convex shape with a protruding portion at a position corresponding to the central portion, and is capable of transmitting light.
It is characterized by:

The invention described in claim 2 is the static eliminator described in claim 1,
One control means for controlling the lighting of all the light-emitting elements;
The present invention is characterized by comprising:

The invention described in claim 3 is the static eliminator according to claim 1 or 2,
the light-emitting elements are arranged in a large number per unit length in a range corresponding to the central portion along the rotation axis direction;
The present invention is characterized by comprising:

The invention described in claim 4 is the static eliminator according to any one of claims 1 to 3,
the light emitting means being configured such that a light emitting element corresponding to the central portion emits a larger amount of light than a light emitting element corresponding to the end portion;
The present invention is characterized by comprising:

The invention described in claim 5 is the static eliminator described in claim 1 ,
the optical element configured such that the amount of light transmitted through the end portion is smaller than that transmitted through the central portion;
The present invention is characterized by comprising:

In order to solve the above technical problem, the static eliminator of the invention described in claim 6 comprises:
a light emitting means having a plurality of light emitting elements arranged along a direction of a rotation axis of the rotating image holding means, and irradiating the image holding means with light;
A control means for controlling the lighting of the light emitting element;
Equipped with
the distribution of the amount of light in the direction of the rotation axis is such that the amount of light is greater in the central portion in the width direction of the medium on which the image is recorded than in the end portions;
The light emitting means is configured such that the amount of attenuation of light is smaller in the central portion than in the end portion, and the distance between the light emitting element and the image holding means is such that the light emitting element corresponding to the central portion is closer than the light emitting element corresponding to the end portion.
It is characterized by:

The invention described in claim 7 is the static eliminator according to any one of claims 1 to 6 ,
said control means reducing the overall amount of light emitted by said light emitting means when the width of the medium being used is small compared to when the width of the medium is large;
The present invention is characterized by comprising:

The invention described in claim 8 is the static eliminator described in claim 7 ,
said control means for reducing the overall light amount of said light emitting means so that a predetermined amount of light is irradiated at an edge of the medium being used;
The present invention is characterized by comprising:

In order to solve the above technical problem, the image forming apparatus according to the present invention is
An image holding means;
a charging means for charging the image holding means;
a latent image forming means for forming a latent image on a surface of the image holding means;
a developing means for developing the latent image on the image holding means;
a transfer means for transferring the image developed by the developing means onto a medium;
a cleaning means for cleaning the surface of the image holding means after transfer;
a charge removing device according to any one of claims 1 to 8 , which removes charge from a surface of the image holding means after cleaning;
The present invention is characterized by comprising:

According to the invention as set forth in claims 1 , 6 and 9 , the configuration can be simplified compared to a case in which separate static elimination means are provided for a plurality of regions in the width direction.
According to the first aspect of the present invention, the amount of light in the central portion can be increased by the optical element.
Furthermore, according to the first aspect of the present invention, the amount of light in the central portion can be increased by using an optical element having a convex central portion.
According to the second aspect of the present invention, the configuration can be simplified compared to a case where light emitting elements are controlled by a plurality of control means.
According to the third aspect of the present invention, the density of the light emitting elements can be changed to make the light amount distribution greater in the central portion.
According to the fourth aspect of the present invention, the light emitting element that emits a large amount of light can be disposed in the center, so that the light amount distribution is greater in the center.

According to the fifth aspect of the present invention, it is possible to increase the amount of light in the central portion relatively with an optical element in which the amount of transmitted light is small at the ends.
According to the sixth aspect of the present invention , the amount of attenuation in the central portion of the light emitting means is small, and the amount of light in the central portion can be increased.

According to the sixth aspect of the present invention , the light quantity at the central portion can be increased by using a light emitting means that is close to the central portion and has a small amount of attenuation.
According to the seventh aspect of the invention , it is possible to prevent excessive static elimination in the outer regions of a narrow medium, compared to when the overall light amount is not reduced when the medium is narrow.
According to the eighth aspect of the present invention , insufficient neutralization at the edge of the medium can be suppressed compared to a case in which the predetermined light amount is not set at the edge of the medium being used.

FIG. 1 is an overall explanatory diagram of an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a diagram illustrating a main part of the image recording unit of the first embodiment. FIG. 3 is an explanatory diagram of the relationship between the medium, the image holding means, the charging means, the cleaning means and the charge removing means in the first embodiment. FIG. 4 is an explanatory diagram of the light amount control according to the first embodiment. FIG. 5 is an explanatory diagram of a static eliminator according to a second embodiment, and corresponds to FIG. 3 of the first embodiment. FIG. 6 is an explanatory diagram of a static eliminator and an image holding means according to a third embodiment. FIG. 7 is an explanatory diagram of a static eliminator and an image holding means according to a fourth embodiment, and corresponds to FIG. 6 of the third embodiment. FIG. 8 is an explanatory diagram of a static eliminator and an image holding means according to the fifth embodiment, and corresponds to FIG. 6 of the third embodiment. FIG. 9 is an explanatory diagram of a static eliminator and an image holding means according to the sixth embodiment, and corresponds to FIG. 3 of the first embodiment.

Next, specific examples of the present invention (hereinafter, referred to as examples) will be described with reference to the drawings, but the present invention is not limited to the following examples.
In order to make the following explanation easier to understand, in the drawings, the front-to-rear direction is defined as the X-axis direction, the left-to-right direction is defined as the Y-axis direction, and the up-down direction is defined as the Z-axis direction, and the directions or sides indicated by arrows X, -X, Y, -Y, Z, and -Z are defined as the front, rear, right side, left side, upper side, and lower side, or the front side, rear side, right side, left side, upper side, and lower side, respectively.
In addition, in the figures, a "・" inside a "○" means an arrow going from the back to the front of the page, and an "X" inside a "○" means an arrow going from the front to the back of the page.
In the following description using the drawings, illustrations of components other than those necessary for the description are omitted as appropriate for ease of understanding.

FIG. 1 is an overall explanatory diagram of an image forming apparatus according to a first embodiment of the present invention.
1, a copier U as an example of an image forming apparatus according to the first embodiment of the present invention has a printer unit U1 as an example of an image recording means. A scanner unit U2 as an example of a reading means and an example of an image reading device is supported above the printer unit U1. An auto feeder U3 as an example of a document conveying device is supported above the scanner unit U2.

A document tray TG1, which is an example of a medium storage means, is disposed above the auto feeder U3. A stack of multiple documents Gi to be copied can be stored in the document tray TG1. A document discharge tray TG2, which is an example of a document discharge section, is formed below the document tray TG1. A document transport roller U3b is disposed between the document tray TG1 and the document discharge tray TG2 along the document transport path U3a.

A platen glass PG, which is an example of a transparent document table, is disposed on the upper surface of the scanner unit U2. In the scanner unit U2 of Example 1, a reading unit U2a, which is an example of a reading unit, is disposed below the platen glass PG. The reading unit U2a of Example 1 is supported along the lower surface of the platen glass PG so as to be movable in the left-right direction, which is an example of a sub-scanning direction. The reading unit U2a is electrically connected to the image processing unit GS.

FIG. 2 is a diagram illustrating a main part of the image recording unit of the first embodiment.
The image processing section GS is electrically connected to a writing circuit DL of the printer section U1. The writing circuit DL is electrically connected to exposure devices LHy, LHm, LHc, and LHk, which are an example of a latent image forming means.
The exposure devices LHy to LHk in the first embodiment are configured, for example, with an LED head in which a plurality of LEDs are arranged in the main scanning direction. The exposure devices LHy to LHk are configured to be able to output writing light corresponding to each of the colors Y, M, C, and K in response to a signal input from a writing circuit DL.
The write circuit DL and the power supply circuit E are controlled in terms of the write timing and the power supply timing in response to control signals from a control section C, which is an example of a control means.
In Fig. 1, photoconductors PRy, PRm, PRc, and PRk as an example of an image holding means are disposed above the exposure devices LHy to LHk. In Fig. 1 and Fig. 2, writing areas Q1y, Q1m, Q1c, and Q1k are configured by areas on the photoconductors PRy to PRk where the writing light is irradiated.

Charging rollers CRy, CRm, CRc, and CRk as an example of a charging means are disposed upstream of the writing areas Q1y to Q1k with respect to the rotation direction of each of the photoconductors PRy, PRm, PRc, and PRk. The charging rollers CRy to CRk in the first embodiment are supported in contact with the photoconductors PRy to PRk so as to be rotatable by the photoconductors PRy to PRk.
Developing devices Gy, Gm, Gc, and Gk, which are an example of developing means, are disposed downstream of the writing areas Q1y to Q1k with respect to the rotation direction of the photoconductors PRy to PRk. The developing areas Q2y, Q2m, Q2c, and Q2k are formed by the areas where the photoconductors PRy to PRk and the developing devices Gy to Gk face each other.

Primary transfer rollers T1y, T1m, T1c, and T1k, which are an example of a primary transfer means, are disposed downstream of the developing devices Gy to Gk with respect to the rotation direction of the photoconductors PRy to PRk. Primary transfer regions Q3y, Q3m, Q3c, and Q3k are formed by regions where the photoconductors PRy to PRk and the primary transfer rollers T1y to T1k face each other.
Photoconductor cleaners CLy, CLm, CLc, and CLk, which are an example of a cleaning unit, are disposed downstream of the primary transfer rollers T1y to T1k with respect to the rotation direction of the photoconductors PRy to PRk.
Dischargers Jy, Jm, Jc, and Jk, which are an example of a discharge means and an example of a discharge device, are disposed downstream of the photoconductor cleaners CLy to CLk with respect to the rotation direction of the photoconductors PRy to PRk.

The Y-color photoconductor PRy, charging roller CRy, exposure device LHy, development device Gy, primary transfer roller T1y, photoconductor cleaner CLy, and static eliminator Jy constitute the Y-color image forming unit Uy, which is an example of a Y-color visible image forming means in Example 1 that forms a Y-color toner image. Similarly, the M-, C-, and K-color image forming units Um, Uc, and Uk are constituted by the photoconductors PRm, PRc, and PRk, charging rollers CRm, CRc, and CRk, exposure devices LHm, LHc, and LHk, development devices Gm, Gc, and Gk, primary transfer rollers T1m, T1c, and T1k, photoconductor cleaners CLm, CLc, and CLk, and static eliminators Jm, Jc, and Jk.

A belt module BM, which is an example of an intermediate transfer device, is disposed above the photoconductors PRy to PRk. The belt module BM is an example of an image holding means, and has an intermediate transfer belt B, which is an example of an intermediate transfer means. The intermediate transfer belt B is made of an endless belt-like member.
The intermediate transfer belt B in the first embodiment is rotatably supported by a tension roller Rt as an example of a tensioning means, a walking roller Rw as an example of a deviation correcting means, an idler roller Rf as an example of a driven means, a backup roller T2a as an example of an opposing means in the secondary transfer region, primary transfer rollers T1y, T1m, T1c, and T1k, and a drive roller Rd as an example of a drive member. In the first embodiment, when drive is transmitted to the drive roller Rd, the intermediate transfer belt B rotates.

A secondary transfer roller T2b, which is an example of a secondary transfer means, is disposed at a position facing the backup roller T2a across the intermediate transfer belt B. The backup roller T2a and the secondary transfer roller T2b constitute a secondary transfer unit T2 of the first embodiment, which is an example of a transfer device. A secondary transfer area Q4 is constituted by an area where the secondary transfer roller T2b and the intermediate transfer belt B contact each other.
A belt cleaner CLb is disposed downstream of the secondary transfer area Q4 in the rotation direction of the intermediate transfer belt B, as an example of a cleaning device for the intermediate transfer body.
The primary transfer rollers T1y to T1k, the intermediate transfer belt B, the secondary transfer unit T2, etc., constitute a transfer device T1+T2+B of the first embodiment as an example of a transfer means. The image forming units Uy to Uk and the transfer device T1+T2+B constitute an image recording unit Uy to Uk+T1+T2+B of the first embodiment.

1, four pairs of left and right guide rails GR as an example of a guide means are provided below the imaging units Uy to Uk. Each guide rail GR supports paper feed trays TR1 to TR4 as an example of a medium storage means so that they can be moved in and out in the front-rear direction. The paper feed trays TR1 to TR4 store recording paper S as an example of a medium.
A pickup roller Rp, which is an example of a removal means, is disposed above and to the left of the paper feed trays TR1 to TR4. A separation roller Rs, which is an example of a separation means, is disposed downstream of the pickup roller Rp in the transport direction of the recording paper S. A paper feed path SH1, which extends upward and is an example of a medium transport path, is formed downstream of the separation roller Rs in the transport direction of the recording paper S. A plurality of transport rollers Ra, which are an example of a transport means, are disposed on the paper feed path SH1.

A manual feed tray TR0 as an example of a medium storage means is disposed in the lower left portion of the copier U. A pickup roller Rp0 is disposed in the upper right portion of the manual feed tray TR0, and a manual feed path SH0 extends from the manual feed tray TR0. The manual feed path SH0 merges with the feed path SH1.
In the sheet feed path SH1, a registration roller Rr as an example of a conveyance timing adjustment unit is disposed upstream of the secondary transfer area Q4. A conveyance path SH2 extends from the registration roller Rr toward the secondary transfer area Q4.

A fixing device F as an example of a fixing means is disposed downstream of the secondary transfer area Q4 in the conveying direction of the recording paper S. The fixing device F has a heating roller Fh as an example of a fixing member for applying heat, and a pressure roller Fp as an example of a fixing member for applying pressure. A fixing area Q5 is formed by a contact area between the heating roller Fh and the pressure roller Fp.
A lower discharge tray TRh, which is an example of a medium discharge section, is formed on the upper surface of the printer unit U1. A discharge path SH3, which is an example of a transport path, extends toward the lower discharge tray TRh above the fixing device F. Discharge rollers Rh, which are an example of a medium transport means, are disposed at the downstream end of the discharge path SH3.

An upper discharge tray TRh2 as an example of a medium discharge section is disposed above the lower discharge tray TRh. An upper transport path SH4 is formed above the fixing device F, branching off from the discharge path SH3 and extending toward the upper discharge tray TRh2.
A reversible roller Rb, which is an example of a medium transport means, is disposed on the upper transport path SH4. A reversible path SH6, which is an example of a medium transport path, branches off to the lower left from the upper transport path SH4 above the branching position of the paper discharge path SH3 and the upper transport path SH4.
A gate GT1 as an example of a switching means is disposed across a branching portion between the discharge path SH3 and the upper transport path SH4 and a branching portion between the upper transport path SH4 and the reversing path SH6. The gate GT1 guides the recording paper S from the fixing device F toward the lower discharge tray TRh, and is supported switchably between a first guide position (second position) for guiding the recording paper S from the upper transport path SH4 to the reversing path SH6 and a second guide position (first position) for guiding the recording paper S from the fixing device F to the upper transport path SH4.
A plurality of transport rollers Ra, which are an example of a medium transport means, are arranged on the reversing path SH6. The downstream end of the reversing path SH6 joins the paper feed path SH1 on the upstream side of the registration rollers Rr.

(Explanation of Image Forming Operation)
In the copying machine U of the first embodiment having the above-mentioned configuration, when an operator places an original Gi on the platen glass PG by hand to perform copying, the reading unit U2a moves from the initial position in the left-right direction, and the original Gi on the platen glass PG is scanned while being exposed to light. When the automatic feeder U3 is used to automatically transport the original Gi to perform copying, the multiple originals Gi accommodated in the original tray TG1 are transported sequentially to the original reading position on the platen glass PG, pass through it, and are discharged to the original discharge tray TG2. Each original Gi that passes sequentially through the reading position on the platen glass PG is exposed to light by the reading unit U2a and scanned. The reflected light from the original Gi is received by the reading unit U2a. The reading unit U2a converts the received reflected light from the original Gi into an electrical signal. When double-sided reading of the original Gi is performed, the original Gi is also read by the reading sensor.

The image processing unit GS receives the electrical signals output from the reading unit U2a. The image processing unit GS converts the electrical signals of the R, G, and B color images read by the reading unit U2a into image information of yellow (Y), magenta (M), cyan (C), and black (K) for forming a latent image. The image processing unit GS outputs the converted image information to the writing circuit DL of the printer unit U1. Note that, when the image is a single-color image, that is, a monochrome image, the image processing unit GS outputs image information of only black (K) to the writing circuit DL.
The writing circuit DL outputs a control signal corresponding to the input image information to the exposure devices LHy to LHk, which in turn output writing light corresponding to the control signal.

When image formation starts, each photoconductor PRy-PRk is rotated. A charging voltage is applied to the charging rollers CRy-CRk from the power supply circuit E. Therefore, the surfaces of the photoconductors PRy-PRk are charged by the charging rollers CRy-CRk. An electrostatic latent image is formed on the surface of the charged photoconductors PRy-PRk by the exposure devices LHy-LHk in the writing areas Q1y-Q1k. The electrostatic latent image of the photoconductors PRy-PRk is developed into a toner image, an example of a visible image, by the developing devices Gy, Gm, Gc, Gk in the development areas Q2y-Q2k.

The developed toner images are transported to primary transfer regions Q3y, Q3m, Q3c, and Q3k that contact the intermediate transfer belt B, which is an example of an intermediate transfer body. In the primary transfer regions Q3y, Q3m, Q3c, and Q3k, a primary transfer voltage having a polarity opposite to the charge polarity of the toner is applied from a power supply circuit E to the primary transfer rollers T1y to T1k. Therefore, the toner images on the photoconductors PRy to PRk are transferred to the intermediate transfer belt B by the primary transfer rollers T1y to T1k. In the case of a multi-color toner image, the toner image on the downstream side is transferred and superimposed on the toner image transferred to the intermediate transfer belt B in the upstream primary transfer region.
After the primary transfer, residues and deposits on the photoconductors PRy to PRk are cleaned by photoconductor cleaners CLy to CLk. The surfaces of the photoconductors PRy to PRk after cleaning are neutralized by neutralizers Jy to Jk. The surfaces of the photoconductors PRy to PRk after neutralization are recharged by charging rollers CRy to CRk.
The single-color or multi-color toner images transferred onto the intermediate transfer belt B by the primary transfer rollers T1y to T1k in the primary transfer areas Q3y to Q3k are transported to the secondary transfer area Q4.

The recording paper S on which an image is recorded is picked up by the pickup roller Rp of the paper feed tray TR1 to TR4 being used. If the recording paper S picked up by the pickup roller Rp is a stack of multiple sheets of recording paper S, they are separated one by one by the separation roller Rs. The recording paper S separated by the separation roller Rs is transported along the paper feed path SH1 by the transport roller Ra. The recording paper S transported along the paper feed path SH1 is sent to the registration roller Rr. The recording paper S loaded on the manual feed tray TR0 is also sent to the paper feed path SH1 by the pickup roller Rp0 via the manual feed path SH0 by the manual feed path SH0.
The registration roller Rr transports the recording paper S to the secondary transfer area Q4 in time with the toner image formed on the intermediate transfer belt B being transported to the secondary transfer area Q4. A secondary transfer voltage of a polarity opposite to the charge polarity of the toner is applied to the secondary transfer roller T2b by the power supply circuit E. Therefore, the toner image on the intermediate transfer belt B is transferred from the intermediate transfer belt B to the recording paper S.

After the secondary transfer, the intermediate transfer belt B has any adhering matter or the like on its surface cleaned by a belt cleaner CLb.
The recording paper S onto which the toner image has been secondarily transferred is heated and fixed when passing through a fixing area Q5.
When the recording paper S on which the image has been fixed is discharged to the lower discharge tray TRh, the gate GT1 moves to the first guide position. Therefore, the recording paper S sent out from the fixing device F is transported along the discharge path SH3. The recording paper S transported along the discharge path SH3 is discharged to the lower discharge tray TRh by the discharge rollers Rh.

When the recording paper S is discharged onto the upper discharge tray TRh2, the gate GT1 moves to the second guiding position, and the recording paper S is discharged onto the upper discharge tray TRh2.
When the recording paper S is printed on both sides, the gate GT1 moves to the second guide position. Then, when the trailing edge of the recording paper S passes through the gate GT1, the gate GT1 moves to the first guide position and the reversing roller Rb rotates in the reverse direction. Therefore, the recording paper S is guided by the gate GT1 and sent to the reversing path SH6.

(Explanation of the static eliminator)
FIG. 3 is an explanatory diagram of the relationship between the medium, the image holding means, the charging means, the cleaning means and the charge removing means in the first embodiment.
Next, we will explain the static eliminators Jy to Jk of Example 1. However, since the configuration of the static eliminators Jy to Jk of each color is the same, we will only explain the static eliminator Jk of color K, and will omit detailed explanations of the static eliminators Jy to Jc of the other colors.
In Fig. 3, the static eliminator Jk of Example 1 has a substrate 1 extending along the photoconductor PRk. The substrate 1 of Example 1 is configured in a flat plate shape extending along the rotation axis direction of the photoconductor PRk. A plurality of LED chips 2 as an example of light emitting elements are arranged on the surface of the substrate 1. In the static eliminator Jk of Example 1, the turning on and off and light amount of all the LED chips 2 are collectively controlled in response to a control signal from the controller C. In other words, the turning on and off of all the LED chips 2 is controlled by a single controller C.

In Example 1, the LED chips 2 used are of the same configuration, and the number of LED chips 2 per unit length is greater in the center in the width direction (photoconductor axial direction) than at the ends. That is, the LED chips 2 are arranged at a higher density in the center than at the ends. Therefore, the static eliminator Jk of Example 1 is configured to emit a greater amount of light in the center in the width direction than at the ends.
The substrate portion 1 and the plurality of LED chips 2 constitute static eliminator main bodies 1-2 as an example of the light emitting means of the first embodiment.

In FIG. 3, the copying machine U of Example 1 can use large size recording paper S1 to small size recording paper S3, and the axial length of the photoconductor PRk is longer than the width of the largest usable recording paper S1. The cleaning blade, which is an example of a cleaning means for the charging roller CRk and the photoconductor cleaner CLk, is also set to a width longer than the width of the largest sized recording paper S1 and shorter than the width of the photoconductor PRk. The static eliminator Jk is also set to a width that covers the width charged by the charging roller CRk.

(Description of the control unit of the first embodiment)
In Fig. 3, the control unit (controller) C, which is an example of a control means of the copier U, has an input/output interface I/O for inputting and outputting signals from and to the outside. The control unit C also has a ROM (read-only memory) in which programs and information for performing necessary processing are stored. The control unit C also has a RAM (random access memory) for temporarily storing necessary data. The control unit C also has a CPU (central processing unit) for performing processing according to the programs stored in the ROM or the like. Thus, the control unit C in the first embodiment is composed of a small information processing device, a so-called microcomputer. Thus, the control unit C can realize various functions by executing programs stored in the ROM or the like.

(Functions of control unit C)
FIG. 4 is an explanatory diagram of the light amount control according to the first embodiment.
The charge removal control means C1 of the control unit C of the first embodiment controls the charge remover Jk to remove the charge from the photoconductor PRk. The charge removal control means C1 turns on and off the charge remover Jk and adjusts the amount of light. That is, when the photoconductor PRk is charged and transferred in accordance with the operation of the copier U, the charge remover Jk turns on, and when the operation is completed, the charge remover Jk is turned off. In FIG. 4, the charge removal control means C1 of the first embodiment reduces the total amount of light from the LED chip 2 when the width of the recording paper S is small compared to when the width is large. Specifically, the charge removal control means C1 of the first embodiment adjusts the total amount of light so that the light amount required for charge removal is irradiated at the ends S1a and S3a in the width direction of the recording paper S used.

(Function of Example 1)
In the copier U of the first embodiment having the above-mentioned configuration, the static eliminator Jk has the LED chips 2 arranged at a high density in the center of the width direction, and the amount of light emitted from the center is large due to the configuration. The static eliminator Jk eliminates static electricity from the photoconductor PRk.
Conventional static eliminators are generally configured to provide the same amount of light over the entire width direction. In conventional configurations, discharge products are generated on the surface of the photoconductor during charging and transfer. These discharge products are removed by the cleaning blade of the photoconductor cleaner. The cleaning blade wears over time due to friction with the photoconductor, but if the developer periodically reaches the cleaning blade, an external additive such as ZnSt (zinc stearate) added to the developer functions as a lubricant to suppress wear. Here, in the paper passing area on the inside of the width of the recording paper S on the photoconductor, the developer reaches the cleaning blade because an image is formed, but in the non-paper passing area on the outside of the recording paper S, the developer is not sent to the cleaning blade. Therefore, the cleaning blade is easily worn in the non-paper passing area. Therefore, the wear of the cleaning blade varies in the width direction, and there is a risk of image quality defects such as color streaks caused by the developer slipping through in the worn area. In particular, when printing is normally performed on small-sized recording paper S, the cleaning blade may wear out inside the large-sized image area, and color streaks may become a problem when printing a large-sized image.

In response to these, Patent Documents 1 and 2 describe a technique in which three (or more) light sources with different widths for irradiating light in the width direction are installed, and the light sources are switched so that the area where an image is formed is neutralized and the area where an image is not formed is not neutralized. In the technique described in Patent Documents 1 and 2, the area where an image is not formed (non-paper passing area) is not neutralized, and the surface of the photoconductor reaches the charging area in a high potential state. At this time, in the charging area, the part that is not sufficiently neutralized has a lack of potential difference with the charger, making it difficult for discharge to occur. Therefore, the generation of discharge products is suppressed, and the wear of the cleaning blade in the non-paper passing area is suppressed.
However, the configurations described in Patent Documents 1 and 2 require multiple light sources with different widths for emitting light, and a configuration for switching on and off with a switch according to the multiple areas divided in the width direction. In other words, multiple light sources and circuits such as switches corresponding to the divided areas and the width of the recording paper used, and a controller for controlling them are required. This makes the configuration complicated, which can easily increase manufacturing costs and cause problems such as a high likelihood of failure.

The static eliminator Jk of Example 1 has a large amount of light in the center in the width direction. Therefore, the amount of light is small at the ends in the width direction, which are often non-paper passing areas, and the amount of static elimination is small. Therefore, discharge in the non-paper passing areas is easily suppressed, wear is suppressed, and the occurrence of image quality defects is suppressed. In Example 1, the amount of light is adjusted by the arrangement of the LED chips 2 in the static eliminator Jk, and no circuit elements such as switches are required for switching. Therefore, the configuration is simplified compared to the configurations that require multiple switches, such as the technologies described in Patent Documents 1 and 2. Therefore, the increase in manufacturing costs and failures are suppressed, and it also contributes to miniaturization. In particular, the static eliminator Jk of Example 1 has only one circuit configuration, so it contributes more to costs and miniaturization than when there are two or more circuits.
In the static eliminator Jk of Example 1, the amount of light is adjusted by adjusting the arrangement of the LED chips 2, and a common LED chip 2 is used. Therefore, compared to using a plurality of LED chips with different performance such as light amount, the parts are commonized, and manufacturing costs can be easily suppressed.
Furthermore, experimental results showed that if the difference in light intensity between the ends and the center is 10% or more, the amount of blade wear at the ends is not a problem compared to the center, and that a difference of 15% or more is even more preferable.

Furthermore, in the static eliminator Jk of Example 1, when the width of the recording paper S used is small, the total amount of light is reduced. If the width of the recording paper S is small, the non-paper passing area becomes wide (an image is formed only in the center in the width direction), and in a configuration in which the amount of light is not reduced, there is a risk that static electricity will be sufficiently eliminated even in the non-paper passing area. In contrast, in Example 1, when the width of the recording paper S is small, the total amount of light is reduced, and the amount of light irradiated to the non-paper passing area is reduced. This further suppresses wear of the cleaning blade.
In particular, in the first embodiment, the total amount of light is reduced so that the amount of light necessary for sufficient static elimination is reached at the edge of the recording paper S. Therefore, the amount of light necessary for static elimination is ensured in the paper passing area, and it is possible to prevent excessive static elimination in the non-paper passing area.

Next, a second embodiment of the present invention will be described. In the description of the second embodiment, components corresponding to those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted.
This embodiment differs from the first embodiment in the following respects, but is otherwise configured in the same manner as the first embodiment.
FIG. 5 is an explanatory diagram of a static eliminator according to a second embodiment, and corresponds to FIG. 3 of the first embodiment.
5, in Example 2, unlike the LED chip 2 in Example 1, LED chips 2' with different light emission amounts are used. Specifically, LED chips with increasing light emission amounts are used in the order of LED chips 2a at both ends, LED chip 2b on the inside, LED chip 2c further inside, and LED chip 2d in the center. Note that the intervals between the LED chips 2a to 2d are set to be equal, unlike Example 1.

(Function of Example 2)
In the static eliminator Jk of Example 2 having the above-mentioned configuration, the configuration is different from that of Example 1, but the distribution of the light amount in the width direction can be the same as that of Example 1. Therefore, like Example 1, it is possible to suppress excessive static elimination at the width direction end of one static eliminator main body (light emitting means) 1-2'.

Next, a third embodiment of the present invention will be described. In the description of the third embodiment, components corresponding to those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted.
This embodiment differs from the first embodiment in the following respects, but is otherwise configured in the same manner as the first embodiment.
FIG. 6 is an explanatory diagram of a static eliminator and an image holding means according to a third embodiment.
6, the static eliminator Jk of Example 3 has a substrate 11, LED chips 12 as an example of a light emitting element supported on the surface of the substrate 11, and a convex lens 13 as an example of an optical element. The LED chips 12 of Example 3 all have the same light emission amount and are arranged at equal intervals in the width direction.
The convex lens 13 has an incident surface 13a on the LED chip 12 side formed in a flat shape along the width direction. Also, the exit surface 13b on the photoconductor PRk side is formed in a convex curved shape in which the center in the width direction protrudes toward the photoconductor PRk side more than the ends according to the light amount distribution. The convex lens 13 is made of a material that can transmit the light from the LED chip 12.
The substrate 11, the LED chip 12 and the convex lens 13 constitute the static eliminator main bodies 11 to 13 as an example of the light emitting means of the third embodiment.

(Function of Example 3)
In the static eliminator Jk of Example 3 having the above-mentioned configuration, the light passing through the convex lens 13 is refracted, and the light on the outer side in the width direction spreads outward. Therefore, the amount of light in the center is relatively greater than the amount of light at the ends. Therefore, Example 3 also has the same light amount distribution as Example 1. Therefore, similar to Example 1, it is possible to suppress excessive static elimination at the ends in the width direction with one static eliminator main body 11 to 13.

Next, a fourth embodiment of the present invention will be described. In the description of the fourth embodiment, the components corresponding to those in the first and third embodiments are given the same reference numerals, and detailed description thereof will be omitted.
This embodiment differs from the first and third embodiments in the following respects, but is otherwise configured in the same manner as the first and third embodiments.
FIG. 7 is an explanatory diagram of a static eliminator and an image holding means according to a fourth embodiment, and corresponds to FIG. 6 of the third embodiment.
7, the static eliminator Jk of the fourth embodiment has an optical filter 16 as an example of an optical element, instead of the convex lens 13 of the third embodiment. The optical filter 16 of the fourth embodiment is configured as a filter that attenuates transmitted light, with the end 16a in the width direction having the greatest attenuation, the inner portion 16b having a smaller attenuation than the end 16a, and the central portion 16c having the least attenuation. Note that the attenuation can be changed, for example, by using different materials (mediums) for the portions 16a to 16c.
The substrate 11, the LED chip 12 and the optical filter 16 constitute the static eliminator main bodies 11 to 16 as an example of the light emitting means of the fourth embodiment.

(Function of Example 4)
In the static eliminator Jk of Example 4 having the above-mentioned configuration, the light transmitted through the optical filter 16 is attenuated more toward the ends. Therefore, the amount of light in the center is relatively greater than the amount of light at the ends. Thus, Example 4 also has the same light amount distribution as Examples 1 and 3. Therefore, as in Examples 1 and 3, it is possible to prevent excessive static elimination at the ends in the width direction with one static eliminator main body 11 to 16.

Next, a fifth embodiment of the present invention will be described. In the description of the fifth embodiment, the components corresponding to those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted.
This embodiment differs from the first embodiment in the following respects, but is otherwise configured in the same manner as the first embodiment.
FIG. 8 is an explanatory diagram of a static eliminator and an image holding means according to the fifth embodiment, and corresponds to FIG. 6 of the third embodiment.
In FIG. 8, the static eliminator Jk of the fifth embodiment has a substrate 21 and an LED chip 22 as an example of a light emitting element supported on the surface of the substrate 21. The substrate 21 of the fifth embodiment has a surface 21a on the photoconductor PRk side that is curved in a convex shape with the center in the width direction protruding toward the photoconductor PRk side more than the ends according to the light amount distribution. The LED chips 22 are arranged on the convexly curved surface 21a at equal intervals in the width direction and are closer to the photoconductor PRk as the LED chip 22 in the center is closer. That is, when the distances between the photoconductor PRk of the LED chip 22a at the end, the LED chip 22b inside it, and the LED chip 22c at the center are L0, L1, and L2, respectively, the surface 21a of the substrate 21 and the LED chips 22a to 22c are configured so that L0>L1>L2.
In the fifth embodiment, the LED chips 22a to 22c themselves have a common light emission amount.
The substrate 21 and the LED chip 22 constitute the static eliminator main bodies 21 to 22 as an example of the light emitting means of the fifth embodiment.

(Function of Example 5)
In the static eliminator Jk of Example 5 having the above configuration, the distance between each of the LED chips 22a to 22c and the photoconductor PRk is farther toward the ends and closer toward the center. Therefore, the light is more likely to be scattered and attenuated at the ends before it reaches the photoconductor PRk, and as a result, the amount of light at the center is greater than the amount of light at the ends. Therefore, the light amount distribution in Example 5 is similar to that in Examples 1 and 3. Therefore, as in Examples 1 and 3, it is possible to prevent excessive static elimination at the width direction ends with one static eliminator main body 21 to 22.

Next, a sixth embodiment of the present invention will be described. In the description of the sixth embodiment, the components corresponding to those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted.
This embodiment differs from the first embodiment in the following respects, but is otherwise configured in the same manner as the first embodiment.
FIG. 9 is an explanatory diagram of a static eliminator and an image holding means according to the sixth embodiment, and corresponds to FIG. 3 of the first embodiment.
9, in the static eliminator Jk of Example 6, the LED chips 2" are arranged at a high density at one axial end (front end) and at a low density at the other axial end (rear end), corresponding to a configuration in which the recording paper S is transported based on one end in the axial direction, i.e., so-called side-register transport. In other words, for all sizes of recording paper S1 to S3, the center of the "area where an image is recorded" was the center in the front-to-rear direction (so-called center-register transport) in Examples 1 to 5, but in Example 6 it is the front end in the front-to-rear direction, and the light intensity distribution in that part is the greatest.
The substrate 1 and the LED chip 2 ″ constitute a static eliminator main body 1 to 2 ″ as an example of a light emitting means of the sixth embodiment.

(Function of Example 6)
In the static eliminator Jk of Example 6 having the above-mentioned configuration, the amount of static elimination light is large at the front end, which is an area where developer often reaches, and the amount of light is small at the rear end, which is an area where developer rarely reaches, as in Example 1. Therefore, in Example 6, as in Example 1, excessive static elimination is suppressed at the rear end in the width direction, where uneven wear of the cleaning blade is likely to occur.

(Example of change)
Although the embodiments of the present invention have been described above in detail, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Modifications (H01) to (H06) of the present invention are illustrated below.
(H01) In the above embodiment, a copier U is shown as an example of an image forming apparatus, but the present invention is not limited to this and can be applied to a facsimile or a multifunction machine having multiple functions such as a facsimile, printer, copier, etc. Also, the present invention is not limited to a multicolor image forming apparatus, but can be configured as a single-color, so-called monochrome image forming apparatus.
(H02) In the above embodiment, the specific numbers exemplified can be changed as appropriate according to changes in design and specifications. Therefore, the number of LED chips, the light quantity distribution, the number and positions of LED chips 2' with different light quantities, the number of each section 16a to 16c of the optical filter 16, etc. are not limited to the exemplified forms and can be changed according to the purpose.

(H03) In the above-mentioned embodiments, it is also possible to combine the embodiments 1 to 6. For example, it is possible to combine the configuration in which the LED chips 2 are densely arranged in the center of the embodiment 1 with the convex lens 13 of the embodiment 3, or to shape the convex lens 13 according to the distribution of the embodiment 6.
(H04) In the above embodiment, the case where there is one static eliminator body is illustrated, but this is not limited to this. If the desired light amount distribution cannot be realized with one static eliminator body, it is possible to use two or more static eliminators. Even in this case, since it is necessary to increase the circuit configuration in accordance with the desired light amount distribution in Patent Documents 1 and 2, it is possible to reduce the number of static eliminator bodies in the present invention.

(H05) In the above embodiment, the convex lens 13, the optical filter 16, and the configuration of changing the spacing between the LED chips 22a to 22c are exemplified as configurations for reducing the amount of light at the ends compared to the center, but this is not limiting. For example, it is possible to use a lens that converges light to the center, or to install an optical fiber in the center so that the amount of light attenuation in the center is reduced.
(H06) In the above embodiment, it is desirable to apply a configuration in which the overall amount of light is increased or decreased depending on the size of the recording paper S. However, in cases where the amount of usable recording paper S is small, it is also possible to adopt a configuration that does not include a configuration in which the overall amount of light is increased or decreased.

1 to 2, 1 to 2', 1 to 2", 11 to 13, 11 to 16, 21 to 22...light emitting means,
2, 2', 2'', 12, 22...light-emitting element,
13, 16...Optical element,
C...control means,
CLy, CLm, CLc, CLk...cleaning means,
CRy, CRm, CRc, CRk...charging means,
Gy, Gm, Gc, Gk . . . developing means,
Jy, Jm, Jc, Jk...static elimination device,
L0, L1, L2 . . . the distance between the light emitting element and the image holding means,
LHy, LHm, LHc, LHk . . . latent image forming means,
PRy, PRm, PRc, PRk...image holding means,
S…medium;
T1+T2+B...transfer means,
U...Image forming device.

Claims (9)

a light emitting means having a plurality of light emitting elements arranged along a direction of a rotation axis of the rotating image holding means, and irradiating the image holding means with light;
A control means for controlling the lighting of the light emitting element;
Equipped with
the distribution of the amount of light in the direction of the rotation axis is such that the amount of light is greater in the central portion in the width direction of the medium on which the image is recorded than in the end portions;
the light emitting means has an optical element disposed between the light emitting element and the image holding means for reducing the amount of light at the end portion compared to the amount of light at the central portion;
The optical element is formed in a convex shape with a protruding portion at a position corresponding to the central portion, and is capable of transmitting light.
A static eliminator characterized by the above. One control means for controlling the lighting of all the light-emitting elements;
The static eliminator according to claim 1, further comprising: the light-emitting elements are arranged in a large number per unit length in a range corresponding to the central portion along the rotation axis direction;
The static eliminator according to claim 1 or 2, further comprising: the light emitting means being configured such that a light emitting element corresponding to the central portion emits a larger amount of light than a light emitting element corresponding to the end portion;
4. The static eliminator according to claim 1, further comprising: the optical element configured such that the amount of light transmitted through the end portion is smaller than that transmitted through the central portion;
The static eliminator according to claim 1, further comprising: a light emitting means having a plurality of light emitting elements arranged along a direction of a rotation axis of the rotating image holding means, and irradiating the image holding means with light;
A control means for controlling the lighting of the light emitting element;
Equipped with
the distribution of the amount of light in the direction of the rotation axis is such that the amount of light is greater in the central portion in the width direction of the medium on which the image is recorded than in the end portions;
The light emitting means is configured such that the amount of attenuation of light is smaller in the central portion than in the end portion, and the distance between the light emitting element and the image holding means is such that the light emitting element corresponding to the central portion is closer than the light emitting element corresponding to the end portion.
A static eliminator characterized by the above. said control means reducing the overall amount of light emitted by said light emitting means when the width of the medium being used is small compared to when the width of the medium is large;
7. The static eliminator according to claim 1, further comprising: said control means for reducing the overall light amount of said light emitting means so that a predetermined amount of light is irradiated at an edge of the medium being used;
The static eliminator according to claim 7, further comprising: An image holding means;
a charging means for charging the image holding means;
a latent image forming means for forming a latent image on a surface of the image holding means;
a developing means for developing the latent image on the image holding means;
a transfer means for transferring the image developed by the developing means onto a medium;
a cleaning means for cleaning the surface of the image holding means after transfer;
a charge removing device according to any one of claims 1 to 8 , which removes charge from a surface of the image holding means after cleaning;
An image forming apparatus comprising:

Images